A 57-year-old woman came to the dentist's office for treatment of a caries on the occlusal surface of the lower right 2nd molar (47). With the patient semi-recumbent, without cervical extension, local anaesthesia was infiltrated and no abnormal reactions were observed. Subsequently, the caries was reamed with the turbine. During the drilling, the patient developed rotational vertigo. The vertigo subsided as soon as work with the turbine was stopped. When the drilling was restarted, the patient again presented rotatory vertigo, which was milder on this occasion, which allowed the filling to be completed without any further problems. The patient was referred to the Otolaryngologist to study her vertigo in response to intense sound (Tullio's phenomenon). The anamnesis, audiological tests (audiometry and impedance audiometry), vestibular tests (recording of vertic-rotatory nystagmus in response to high intensity sound stimuli), neurophysiological tests (recording of abnormal vestibular myogenic evoked myogenic potentials) and computed tomography demonstrated the existence of a dehiscence of the right superior semicircular canal.

